You....jesus. I can't even accurately describe the levels of WTF.
Dissimilar metals are not required. Copper plate, copper block, copper fittings, copper cooling block. I say this because it's the system I've run for literal years. With distilled water. No visible corrosion similar to what was demonstrated. Likewise, there are self contained aluminum systems. The problems come from things like passivated aluminum fittings, copper blocks with a nickel plated surface, and all of the other shenanigans.
You do not understand metals. Tempering is a process by which you alter the mechanical properties of a metal by adjusting the grain boundary formation. If you let the thing cool really slow it's annealing, where the grain boundaries form roughly of the same size and largely at random. This isn't 100% true depending upon material size, as slower cooling forms much larger grains, but it's largely accurate. If you temper a thing by heating and then rapidly quenching it you get a part with very small outer grains and an internal stress situation. This creates something where the outside is very stable, the inside is a little less stable, but the net is something like a sword, where the hardness change allows the metal to enter certain loads better than would be possible in a homogeneous formation. This also starts a much larger discussion of work hardening, which stretches the grains in the direction of work. That makes the material more resistant to future work that applies work in the same direction. This is why work hardening materials (like some stainless steels or Incolnel) absolutely eat through bits and need annealing processes to bring those grains back to a workable condition.
What you have not seen above is anything about electrochemistry. Dissimilar metals are 100% about electronegativity...which is not a function of working the metal. I don't know what insanity possessed you to claim this it's like claiming that by working copper pipes you can magically prevent rusting...which is just pants on head crazy. Dissimilar metals, like the nickel plated or aluminum item that was shown, in an otherwise copper rich system, is the issue...not the distilled water. I cannot begin to tell you what insanity you are espousing...and I hope to god that you listen.
If you actually want to start educating yourself, I suggest looking up Martensitic steel. Once you understand the crystalline structure, grain boundaries, thermal treating, and everything else you may one day understand that the structure of a metal has nothing to do with CHEMICAL properties, and only its MECHANICAL properties. If you're looking at a claimed reduction reaction in an aqueous solution you'll never see someone factor in work hardening or crystalline structure unless they are crazy enough to try and pull a reaction rate calculation...which also runs based on geometry and not mechanical structure. But, I am reaching to try and give you the benefit of doubt regarding ignorance.
Two words. Buffer solution.
This, for me at least, was high school chemistry. Let me explain this to you really simply, but please don't take offense if it's obvious to you.
If you take sugar, it dissolves in water. Add more, and more, and eventually it starts falling out of solution. It doesn't stay out of solution, it is in fact swapping some in solution for some out of solution, but this swap rate is very low. Now try it with salt. Salt, the table kind, is sodium chloride. In water it dissolves into sodium+ and chlorine- ions. Keep adding salt, and eventually the same thing happens. The capacity for Na+ and Cl- ions is reached. What if you then added a bunch of some other type of salt? This is the fun bit. You now have magnesium chloride (MgCl2) What starts falling out of solution?
That's right, table salt.
What?
Yes, the water now has Na+, Cl-, and Mg2+ ions. The Cl- ions are at their peak, so what happens? Well, there are already ions in the solution, right? Those H+ and OH- ions in the water aren't just for show. The salt actually stabilizes the pH of the solution, such that if you were to suddenly add a bit of acid to said solution (like carbonic acid formed when carbon dioxide dissolves in water) it would resist changing the ion balance, and thus resist changing pH.
Likewise, your pool uses the same stuff that bleach is made out of. Sodium hypochlorite. The point of this chemical is to change the pH...and it's why even people using salt pools can see value from adding bleach. Ironically enough, the goal of bleach is to kill stuff. Specifically plant life, pond scum, and other critters that would foul the water. By introducing a bunch of extra Na+, OCl- ions into the system you screw with the balance of H+ and OH- ions...and if you then add Na+ and CL- ions you can create a solution that balances the pH outside of the range stuff needs to live, and thus create crystal clear water in your pool.
So you are aware, there are several commercial solutions that already do this. A literal pinch of salt (electrolyte), and a minor lean towards being basic, and you've got a growth inhibitor. It's funny that once you understand the chemistry behind things you suddenly start understanding how they sell using snake oil because people just don't have the background to understand this...because high school might have been a long time ago and they probably didn't care a bunch about it when they were there anyways. pH boosters, stabilizers, anti-corrosion agents...these are shiny new ways of selling water+salt+acid or base.
Brass is tin+copper. Copper is copper. Brass does not fall apart...because the crystal structure allows for replacement in similar metals. Jesus, this has been known since the literal bronze age, which is an alloy of copper and zinc. Also something fundamentally stable when produced.
Solder is not generally used in pressure fittings...which are machined copper and plastic tubing. Copper is not preferred for machining given that it is expensive, gummy when worked, and did I mention pretty unforgiving? Not favored is different from not made, because $10 for a fitting definitely motivates niche production of these. Again, I know because I've bought them.
System in question ran weekly from 2011 to 2021 (only monthly now). Three total water changes. Distilled water and a small shot of vinegar to initially condition and test the system. Drained, then filled with pure distilled water from the gallon jug. The rest gets added to my clothing iron, so when it evaporates my clothes aren't mineral rich and crunchy.
How about another reality? How about cars? How about them literally being able to run with water more efficiently than with anti-freeze...which is still mostly water with glycols? Most cars utilize an aluminum motor block, an aluminum radiator, and can run for literal decades without the system completely falling apart. Historically of course the inclusion of glycol was made to retard the reaction of iron blocks and aluminum radiators, because in the 1950s they were aware of the galvanic decay. I mean, they also generally utilize a set of block soldered together as their radiator to dramatically decrease the cost of manufacture, and the very low glycol amount in the radiator is generally viewed as better given that the water flowing around in it is often well past the point where regular water boils (thus being necessary to add something to push that boiling point to prevent a runaway thermal event given cavitation of the fluid along the metal surface functionally prevents any thermal transfer via the fun of the Leidenfrost effect. But that's another entire ball of concentrated crazy.
Man, you really seem like you "know" what is going on, but have PHB syndrome. That is to say Pointy Haired Boss syndrome. A condition characterized by the absolute knowledge of a thing because you know science, but whenever that core science is demonstrated wrong you cannot admit that you're ignorant and thus have to shout louder that you know what you are talking about because the science doesn't lie.
Let me leave you with an example of what I'm talking through...and let me explain why "proper coolant" is not an answer.
Amazon link, water cooler starter kit. It starts out good...and then gets stupid. Aluminum fittings...fine. Aluminum radiator...fine. Plastic reservoir...also fine. Aluminum plugs. Good. Copper CPU block...WTF. They are selling you a solution that is 80% good, and then it fails on step one with a copper block that will rapidly accumulate issues if anything is used inside of it. For about double the cost, you can go entirely copper (
Alphacool starter kit). Note it uses a ton of copper, and nickel plated copper. The Nickel isn't ideal...but it is also a plating over the copper. Based on the fact that it isn't falling apart, these metals are more than similar enough to coexist without galvanic reductions. It's almost like when "professional" solutions can't even understand what dissimilar metals will create...so it's entirely reasonable for somebody like der8auer to put out a video saying that you NEED their fluid, and claim that distilled water is the problem. It's 100% crap, but it's the very simple answer that makes stupid people feel like they're smart enough to solve a problem...even if they never really had the problem...because you are solving a discrepancy in chemistry and not a problem magically inherent specifically and only to distilled water.
I'll finish by stating the painfully obvious. The galvanic reaction is what is assumed to be happening. Rusting is not only galvanic reactions...so the old friend GIGO makes an appearance. Garbage in, garbage out. Trying to retroactively be great because you knew that glycol was required, and anybody not using it is stupid, is showing that you can buy into the BS. Congrats. The now 13 and change year old system that I've got, with distilled water, isn't fouled. Either that means my distilled water had magic pixie dust, or you've got a problem with your rant that can be summed into a single word. Reality.
